Candles have been known for many centuries going back to the eighth century B.C. The nature of candles is described in Ullmann's Encyclopedia of Industrial Chemistry, Volume A5 at pages 29-30 where it is seen that candles are made from paraffin, beeswax and stearin as basic materials, and where a host of additives may also be present.
It is not surprising that with candles and wax becoming increasingly more important attention was paid as to how to stabilize the said materials. At the National Candle Association Meeting in Houston, 1994, R. van der Vennet presented a paper on “Antioxidants in Wax—Replacement of BHT” touting the use of Vitamin E (tocopherol) as an antioxidant to prevent the yellowing of wax when oxidized. WO 94/13736 describes the same invention.
EP 359,488 A3 and EP 133,964 B1 describe stabilized waxes used in cosmetics where the waxes are the same or similar to those used in candles.
EP 5,922 A1 describes lip cosmetics where the waxes are useful in lipsticks and are related to those useful in candles.
U.S. Pat. No. 5,879,694 describes in detail transparent gel candles both in composition and structure. The use of BHT as an antioxidant is mentioned.
At the National Candle Association Technical Meeting on Apr. 16, 1998, F. A. Ballentine et al., presented a paper entitled “Inhibiting Color Fading of Dyed Candles with CYASORB® Light Absorbers” in which the general theories of thermal oxidation and photodegradation are discussed along with data on the effect of light absorbers on color stability of dyed candle waxes. The light absorbers compared are 4-octyloxy-2-hydroxybenzophenone UV-531; 4-methoxy-2-hydroxybenzophenone UV-9; 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole UV-5365; 2-(2-hydroxy-5-tert-octylphenyl-2H-benzotriazole UV-5411 and 2-(2-hydroxy-3,5-di-tert-amylphenyl)-2H-benzotriazole UV-2337).
U.S. Pat. No. 5,964,905 teaches dyed and scented candle gels containing triblock copolymers and a hydrocarbon oil of high flash point. This reference teaches that a light (UV) absorber may be used to improve the shelf stability of the candle color when exposed to visible or ultraviolet light. Two preferred absorbers are ethylhexyl p-methoxycinnamate (PARSOL® MCX, Roche) and 2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole (CYASORB® 5411, Cytec).
WO 00/22037 teaches the stabilization of solid, shaped and colored wax articles, including candles, using a malonate UV absorber which may optionally contain a hindered amine moiety as part of the malonate compound structure. The wax articles are dyed with a variety of oil soluble dyes and pigments. The samples protected by dimethyl p-methoxy-benzylidinemalonate exhibited better resistance to discoloration that did samples stabilized with selected benzotriazole or benzophenone UV absorbers.
Japanese Hei 3-278554 teaches that wax crayons (drawing materials) colored by organic pigments can be stabilized by a hindered amine and/or benzotriazole.
In respect to wax stabilization, the use of selected hindered amines and/or benzotriazole UV absorbers is also known in the prior art as seen in U.S. Pat. Nos. 3,530,084; 4,379,721; 4,616,051 and 5,964,905 and copending applications Ser. Nos. 09/495,495, 09/495,496 and 09/741,583.
U.S. Pat. Nos. 4,046,737; 4,021,432 and 4,049,647 teach piperidine derivatives having substituted by alkyl, alkenyl or alkynyl groups of 1 to 20 carbon atoms.
Japanese Sho 57-137,358 describes piperidine derivatives substituted on the N-atom by a group containing a polymerizable double bond.
EP 300,160 and Japanese Hei 11-263,884 depict piperidine dervatives substituted on the 4-position by a monocarboxylic acid of 16 to 24 carbon atoms. The resulting hindered amine is useful for stabilizing lubricating oils, cosmetics and polyolefins.
U.S. Pat. No. 4,376,836 disclose triazylaminotriazines substituted by hindered piperidine groups where the longest chain in said molecules contain 18 carbon atoms. These molecules are used to stabilize polyolefins.
U.S. Pat. No. 4,319,030 teaches alkylated diaza-spirodecanes which may contain alkyl groups of 1 to 30 carbon atoms. These compounds are used as stabilizers for polyolefins.
U.S. Pat. No. 4,986,932 describes polyolefin compositions containing a benzotriazole or benzophenone UV absorber and a hindered piperidine substituted on the 4-position by a ester group containing 16-24 carbon atoms.
U.S. Pat. No. 4,308,362 discloses copolymers of polymerizable hindered piperidine derivatives which are useful for the stabilization of polyolefins.
U.S. Pat. No. 4,198,334 teaches substituted malonic acid derivatives containing hindered piperidine derivatives which may be substituted with alkyl groups of 1 to 20 carbon atoms.
U.S. Pat. No. 4,496,649 describes color photographic recording material containing hindered piperidine derivatives, but containing aromatic moieties in the molecules.
U.S. Pat. No. 4,141,883 discloses 2,2,6,6-tetraalkylpiperidine compounds substituted on the 4-position by an alkyloxy or acyloxy group of 1 to 18 carbon atoms. These materials are useful for stabilizing polyolefins.
U.S. Pat. No. 4,471,417 teaches poly-bis-triazinylimides which contain hindered amine piperidine moieties and alkyl groups of 1 to 18 carbon atoms. These compounds are useful for stabilzing polyolefins.
U.S. Pat. No. 4,533,688 discloses tris(piperidylaminotriazylamino) compounds which contain alkyl moieties of 1 to 18 carbon atoms. These compounds are useful for the stabilization of polyolefins
U.S. Pat. No. 5,204,473 and copending application Ser. No. 09/257,711 describe hindered amine compounds related to the instant compounds, but without the long chain substitution.
None of these references teach the instant long chain hindered amine compounds themselves or the superior performance provided when said long chain hindered amine compounds are used alone or in conjunction with a UV absorber and/or antioxidant to stabilize candle wax and other compositions subject to degradation.